Anode formed of lead base and duriron



April 2, 1968 R. c. SABINS v I ANODE FORMED OF LEAD BASE AND DURIRONFiled Nov. 6, 1964 ok mm vm QM INVENTOR.

HOLLAND C. SAB/NS A T TORNE Y 3,3762% Patented Apr. 2, 1968 lice3,376,209 ANODE FORMED 01F LEAD BASE AND DURIRON Rolland C. Sabins, 522Catalina Blvd, San Diego, Calif. 92106 Continuation-impart ofapplication Ser. No. 407,302, Oct. 29, 1964. This application Nov. 6,1964, Ser. No. 412,873

Claims. (Cl. 204-196) The present invention relates to an electrolyticsystem and to an anode for said system. More particularly, the presentinvention is directed to an electrolytic system for preventing galvanicdissolution of cathodic material and is directed also to an anode whichis relatively inexpensive yet has the characteristics of expensivesubstances such as platinum.

The present invention is a continuation-in-part of my copendingapplication Ser. No. 407,302, filed Oct. 29, 1964, now abandoned.

In practicing the present invention, an extraneous source of directcurrent is impressed upon the system to increase the potential of thecathode to above its dissolution potential.

It is known that when an attempt is made to use a single body of somesubstances, such as lead, as an anode in a galvanic system employing,for example, sea water as the electrolyte, such substances becomepassive to the flow of current and therefore can function as an anodeonly during the period prior to the substances becoming passive.

I have discovered that by physically associating several of theelements, such as iron and silicon in intimate contact with and exposedto the outer surface of such substance, such as lead, such mass becomesa composite anode and remains sutficiently active so that the entireouter surface thereof, which is exposed to the electrolyte, functionsanodically and that such substance ceases to dissolve after being coatedby a compound including the substances, such as lead, and the substancessuch as iron and silicon which are decomposed by an electric currentwhile in the electrolyte.

Further features and the advantages of the present invention will beapparent from the following description, reference being bad to theaccompanying drawing wherein a preferred embodiment of the invention isillustrated.

In the drawing:

FIG. 1 is a diagrammetic view illustrating a galvanic system wherein myinvention is employed;

FIG. 2 is a fragmentary view of a metallic structure of cathodematerial, as for example, the hull of a steel ship, together with thefragmentary view of the improved anode;

FIG. 3 is a sectional view of the anode taken on line 3-3 of FIG. 2; and

FIG. 4 is a fragmentary sectional view taken along line 44 of FIG. 2,but on a larger scale.

Referring more in detail to the drawing and particularly to FIGS. 2 and3. I have shown a cathode at 20, which may be any metallic object orobjects which is or are to be adapted to be polarized and in which it isdesirable to maintain a substantially uniform polarization of the entiresurface which could be affected by galvanic action. Thus, for example,the cathode may be the hull of a ship and is herin shown as such. Thecomposite anode is shown at 22 and will be described more in detailhereinafter.

The electrolyte may be any suitable compound, such as water or earth.For illustrative purposes, the cathode is shown as embedded in anelectrolyte, for example sea water, the level of which is indicated bythe dot and dash lines 22.

1 face of the lead, passivity of the anode The cathode 20, anode 22 andelectrolyte are connected in galvanic relationship through a circuitincluding a source of direct current. This source of direct current isillustrated by two wires 24 and 26, 24 being connected to the negativeterminal and 26 to the positive terminal of the source of directcurrent. The circuit includes a wire 24, ammeter 28, wire 30, variableresistance 32, wire 34, cathode 20, the electrolyte, anode 22 and wire26.

To protect metal from corrosion, the relative potential at the surfaceof the metal must be increased to transpose the normal positive ionicsurface state to an impressed negative ionic state. For example, a steelstructure cathode has a potential of 630 millivolts with reference to asilver-silver chloride reference anode. It is known that to protect theshipss hull, made of steel, from corrosion in sea water, a potentialshould exist of approximately 890 millivolts, depending upon varyingfactors, and accordingly the potential of the steel cathode must beraise approximately 260 millivolts to prevent galvanic corrosion ofdissolution of the metal, which corrosion or dissolution results inpitting. This increasing in potental is accomplished by subjecting thecathode to the electron flow in the external circuit. The variableresistance 32 is used to regulate the potential to that necessary forraising of the potential of the cathode.

The reference electrode is shown at 36 which is connected with thecathode 20 by wire 38, millivoltmeter 40 and wire 42.

Some compounds, and a number of the elements, enter a passive state whenthey are functioning as an impressed current anode in certainelectrolytes subject to required current density and time. That is, thesurface coating material becomes more passive to the passage ofelectrons when the electrolyte is decomposed by the current flowingtherethrough, as for example, in the ionic exchange phenomena. Incertain of these elements or compounds, the passivity thereof increasesto such an extent that it substantially completely isolates the surfaceconductive of the electrode from the electrolyte enviornrnent. Such istrue with respect to the metals aluminum, lead, and other metalliccompounds.

I have discovered that by physically associating, with an anode 22formed of a lead base a small piece or small pieces of the elements ironand silicon at the sur- 22 is checked, i.e., after a certain stage ofdecomposition of the electrolyte, no further dissolution of the leadtakes place. Upon reaction with the electrolyte, a compound is formed ina thin layer only about the entire surface of the composite anode whichis being subjected to the electrolyte. It is belived that this compoundis a peroxide of lead. Due to the presence of the iron and silicon atthe surface of the lead, the forming of the compound stops at a stage inwhich the entire surface of the whole anode functions as an anode butwithout further dissolution of the lead.

Thus, in effect, the entire surface of the relatively inexpensive leadfunctions to perform substantially the same service as an equal area ofthe highly expensive platinum in that it is relatively inert, yetfunctions as an anode.

My observasion has been that the entire surface of the anode functionsas an anode, since gases are evolved throughout this entire area, mostof which gases as yet have not been identified but is chlorine as wouldbe the case if the entire surface of the anode was platinum anodesurface.

The iron and the silicon should be in intimate contact with the lead,that is, both of these elements should be fastened in some manner to thelead. The iron and silicon could be in the form of a unit and thiscomposition can be pressed or clamped on to the lead. In one form of theinvention, balls, shots, or fine pieces of the composition 43 of ironand silicon are entered into the mold at the time that the lead is castin the desired shape. The composition being less dense than lead, itwill float to the top of the lead casting and therefore be exposed tothe surface of the lead. These balls, shots, or pieces are in the formof a random pattern and the composition comprises 80% to 85% of iron and15% to respectively, of silicon. The composite anode 22 need includeless than one percent of the composition of iron and silicon forsatisfactory results. Excellent results were achieved using lead and acomposition sold under the trademark Durion.

Preferably the anode comprises a series of lead tubing or cables, havingcast therein and at the surface thereof, the balls, shots, or pieces ofthe composition of iron and silicon. These lead cables are shown at 44.These cables 44, extend longitudinally and are suitably fastened to thecathode, herein shown as the outer side of the hull of the ship. Theyhave a diameter of three-fourths inch, in actual practice. Verticallyextending steel plates 48 are suitably welded to the outer surface ofthe hull. They are tapped and threaded as at 50 for receiving bolts 52.The composite anode 22 also includes a plurality of vertically extendinganode parallel bars 54, each having a plurality of transverse orhorizontally extending semicircular grooves 56 for receiving the cables44. These bars 54 are formed of the same material as the cables 44 andalso carry at the surface thereof, the composition iron and silicon. Theanode including the cables 44 and the bars 54 are insulated from directcontact with the hull of the ship and likewise, the plates 48 bydielectric material such as vertically extending strips 58 and 60. Thenylon strip 58 is provided with three transverse or horizontallyextending semi-circular grooves 46. The grooves 46 in the nylon strip 58and groves 56 in the bars 54 complement the cables 44. The nylon strip60 is provided with semi-circular grooves 62 which extend transversely,i.e., horizontally and these grooves complement the periphery of thearcing shape of the 'bars 54. The bolts 52 pass through holes 64 and 66,respectively, in the nylon strips 58 and 60 and when fastened securely,the composite anode including cables 44 and bars 54 are secured to theplate 48.

Steel bars 68 and 70 are disposed, respectively, above and below theanode and are welded to the outer surface of the hull and thereby assistin guarding the anode should the ship encounter wharfs or the like.

The coating is not shown in FIGS. 2 and 3, but is shown at 72 and therandom dispersement of the composition of iron and silicon is shown at43. While such dispersement is shown in elevation in FIGS. 2 and 3, suchis for illustrative purpose only since the coating 72 covers the entiresurface of the composite anode 22 as shown in FIG. 4.

The word cable as herein used may take various forms such as tubing,strands of wire, and may have shapes other than cylindrical.

Thus, it is apparent from the foregoing that I have materially reducedthe cost of inert anodes since the same results are achieved for likeamount of surfaces heretofor deemed necessary in noble metals such asplatinum or lead alloyed with a noble metal,

While the method herein ferred method, it is to be understood that othermethods may be adopted falling within the scope of the claims thatfollow.

I claim:

1. A control system for preventing corrosion ofv a metallic structurewhich is subjected to an electrolyte, comprising in combination:

(A) a source of direct current having the negative side thereofconnected with the structure; and

(B) A composite of said source trolyte, said anode comprising a alloy ofiron and silicon in intimate contact and exposed to the electrolyte atthe outer surface of said lead base to maintain the anodic activeness ofthe entire surface of the lead base.

2. A system as defined in claim 1, in which said alloy comprises to ironand 15% to 10% of silicon.

3. A system as defined in claim 1, in which said alloy constitutes afraction of one anode.

4. A system as defined in claim 1, in which said alloy constitutes afraction of one percent of the composite anode, and in which said alloycomprises 80% to 85% iron and 15% to 10% of silicon.

5. A system as defined in claim 1, characterized in that of current andsubjected to the elec pead base and an the lead base is an elongated barinsulatingly fastened.

to the structure.

6. A system as defined in claim 1, characterized in that the structureis a hull of the ship and said anode is fastened to the hullsubstantially horizontally and below the water line.

7. A composite anode comprising:

(A) lead base;

(B) and an iron-silicon alloy exposed at the outer surface of the leadbase.

8. An anode as defined in claim 7, in which the alloy constitutes afraction of one percent of the composite anode.

9. An anode as defined in claim 8, in which the alloy comprises 80% to85% iron and 15% to 10% silicon.

10. An anode as defined in claim 7, in which the alloy comprises 80% to85% iron and 15% to 10% silicon.

References Cited UNITED STATES PATENTS 546,328 9/1895 Hoepfner 204-290628,676 7/1899 Pollak 136-76 1,302,959 5/1919 Page 204-290 1,788,485 1/1931 Gunderson 204-196 1,984,899 12/1934 Smith 204-196 3,043,765 7/1962Bryan et al. 204-196 3,108,939 10/1963 Sabins 204-196 3,284,333 11/1966Parsi et al. 204 -196 3,294,667 12/1966 Giufirida 204-196 FOREIGNPATENTS 77,881 10/ 1894 Germany.

HOWARD S. WILLIAMS, Primary Examiner. T. TUNG, Assistant Examiner.

described constitutes a preanode connected to the positive side withpercent of the composite UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3,376,209 April 2 1968 Rolland C. Sabins It iscertified that error appears in the above identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 1, line 51 "cathode" should read cath l ne 59, 3." should read 3,line 60, cancel 22 1111i 65, cancel "be". Column 4, line 12, "pead"should read ea Signed and sealed this 5th day of August 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer WILLIAM E. SCHUYLER, JR.

7. A COMPOSITE ANODE COMPRISING: (A) LEAD BASE; (B) AND AN IRON-SILICONALLOY EXPOSED AT THE OUTER SURFACE OF THE LEAD BASE.